Electrochemical methods and devices for determining analyte concentrations in fluid samples find wide application in the treatment and management of medical conditions such as diabetes. Individuals suffering from diabetes monitor their blood glucose concentrations using such methods often several times per day.
Electrochemical methods generally rely upon the correlation between a current, a potential or accumulated charge and the concentration of analyte, typically in conjunction with a reagent that produces charge carriers when combined with the analyte. The electrochemical biosensors for performing the tests are typically disposable test strips having a reagent disposed thereon that chemically reacts with a biological fluid such as blood. The test strip is mated to a test meter such that the test meter can measure the reaction between the analyte and the reagent to determine the concentration of the analyte. For electrochemically-based test strips, the electrical signal is transferred to the meter through electrical contact pads on the test strips and contacts within the meter strip port connector.
A known technique of manufacturing a test strip involves using a metallized polymeric film and forming a conductive electrode pattern on the film. The electrode pattern can be formed by a suitable etching process, including laser ablation or chemical etching, to remove the conductive material from the film leaving in place a conductive electrode pattern interlaced with exposed substrate material. The electrode pattern therefore is defined by a gap of exposed film or substrate material between the conductive material.
Applicants have discovered that on certain prototype test strips made via the laser ablation processes, deposition of the reagent on the electrode pattern was not uniform. Applicants have also discovered that on such prototype test strips, the ability of an analyte sample to consistently fill the reagent and electrode sensing area via the capillary effect was poor. Applicants believe that these issues would lead to a poorly performing test strip.